1. Field of the Invention
The present invention relates to a lamination molding method and a lamination molding apparatus thereof, in more details, a material to be laminate-molded (hereinafter referred to as "the material" comprises a resin layer and a lamination member having convex shapes, wherein a lamination is carried out while the convex shapes of the lamination member is embedded in the resin layer and the surface of the molded products is kept smooth.
2. Description of the Related Art
As an example of the molded products, an IC card is adapted to be embedded with an integrated circuit (IC chip) having an operating and memorizing functions within a plate-like card such as plastic, in addition a magnetic stripe is provided thereon and a necessary information and design are added with engraving such as printing and embossing, or further, the surface is applied with a pear skin. As IC cards, there are a contact type in which a terminal of IC card is exposed on the card surface to be adapted to contact with contact mechanism of such as computer to carry out sending and receiving data, and a non-contact type (wireless) in which, by combining the IC chip and a coil-like antenna and such (hereinafter referred to as "coil") embedded in the IC chip can respond to such apparatus for sending and receiving merely while passing by it. As a substrate for the IC card, in general, a vinyl chloride resin or polyethylene terephtalate (hereinafter referred to as "PET") and such are used as resin layer. And, in order to mold the IC card in lamination, when using PET as a substrate for a plate-like card, it has been carried out to adhere the IC chip or coil to the basic material using an adhesive. Such adhesive forms an embedding layer for the IC chip and the coil. Further, when using a vinyl chloride resin, it has been carried out to melt this vinyl chloride resin layer, thereby, the IC chip and the coil have been embedded in lamination therein.
Thus, in case where, by melting a resin layer and laminate- molding such convex shape which, as it is, becomes as a lamination member like the IC card and the coil, such a molded product having a smooth surface as used for the IC card is molded, a hot vacuum pressure press, as disclosed in Patent Publication Hei 4-52200, has been used.
A vacuum hot press comprises in general a fixed mold, a movable mold which comes close to and separates from the fixed mold for closing and opening molds, a cylinder mechanism enabling the movable mold to be displaced for closing and opening, a plurality of heating plates 30 (see FIGS. 19 and 20) disposed at multiple steps between the fixed mold and the movable mold, a heating means 31 provided in each heating plate 30 to melt a resin layer, a chamber for forming an air-tight chamber which is provided in such a manner as it surrounds the heating plate disposed between the fixed mold and the movable mold and a suction means for depressurizing the chamber to form a vacuum atmosphere in the chamber. Each heating plate 30 is formed from a rigid member, the surface 35 of which, for pressurizing the material, is smooth and not deformable.
For molding the material while embedding it in a resin layer, using such vacuum hot press, first carrying the material between the heating plates 30, 30, forming the air-tight chamber by clamping, depressurizing the air-tight chamber to form a vacuum atmosphere, heating and melting the resin layer of the material by each of the heating plates 30 and pressurizing the material by clamping the movable mold. Thus molded products resin layer is formed in such a manner as the molten resin is pressed by the smooth surface 35 of the heating plate 30, so that its surface is also molded smooth.
On the other hand, as other example of the molded products, there is a circuit substrate for a printed circuit board, which is, in general, formed by overlapping an insulating layer consisting of epoxy resin, phenol resin and thermosetting resin such as polyimide derivative and a copper foil forming an electric conductive layer and laminating those by pressurizing and heating in a single layer, then a given circuit pattern is formed on the electric conductive layer such as copper foil by a post-treatment such as etching. And from the recent request for a miniaturized circuit board, a multiple-layered printed circuit board which is formed in such a manner as through insulating layers many circuit patterns are laminated have been used many times. For laminate-molding of the multiple-layered circuit board, on the circuit pattern formed on the surface of the insulating layer of the circuit board, so called a build-up process, in which further a resin layer which will become an insulating layer and an electrical conductive layer which becomes a circuit pattern are simultaneously or in turn laminated, is carried out. For reference, in general, the shape of each circuit pattern formed in multiple layers through a resin layer having electric insulation property may be different respectively.
By the way, in the case where any resin layer having an insulation property is laminated on the surface thereof, if any air bubble is generated and remained between a circuit substrate on which a circuit pattern is formed and an electric-insulation layer to allow a void to be generated, such voids may swell at the time of a post-process such as a heat-treatment for instance molten solder bath using a high temperature and break an electric-conductive layer laminated or an electric-insulation layer formed from an insulation layer, so that there is anxiety of causing to deteriorate electric-conductivity and insulation. Therefore, in order to prevent any void from being generated, as well as in the molding of the IC card, using a vacuum press it has been carried out to make a laminate molding for a multiple layered circuit substrate under the vacuum atmosphere.
As referred to FIGS. 19 and 20, in the case where an insulation resin layer hb is laminated on the circuit substrate ha formed with a circuit pattern ha2 by the vacuum hot press thus formed as mentioned above, in the stated where the circuit substrate ha and the insulation resin layer hb are overlapped, those are carried in between the heating plates 30, 30 respectively, and the chamber is closed and depressurized by the suction means, to the fixed mold the movable mold is made to come close to clamp the heating plate 30 for pressurizing the circuit substrate ha and the insulation resin layer hb carried in between the heating plates 30, 30, and is heated with the heating means 31. The heated insulation resin layer hb is embedded without voids in the surface of the circuit substrate ha by being molten and fluidized, after that it is solidified due to a chemical reaction occurring at a given temperature. For reference, to the insulation resin layer hb pressurized by the heating plate 30 a resin film layer f is adhered in such a manner as it exists between the heating plate 30 and the insulation resin layer hb. Further, to ensure the mutual insulation property of the insulation layer ha 1 and the circuit pattern ha 2 embedded in the thickness direction of the insulation layer ha 1, the thickness of the insulation resin layer hb is adapted to be settled in such a manner as the thickness of the insulation layer ha 1 after lamination becomes a given value
Further, when a given circuit pattern is formed by etching the electric-conductive layer such as copper foil laminated on the surface of the circuit substrate through the insulation layer, a photo-resist forming layer having a photo-sensitive layer is laminated on the copper foil of the surface of the circuit substrate with a laminator, after that, an exposing process for developing the photo-sensitive layer by exposing to an illumination is carried out. In this exposing process, when a light is illuminated on the photo-sensitive layer, if the surface of the copper foil on which the photo-resist forming layer is laminated, further, the surface of the insulation resin layer on which the copper foil is laminated are not smooth, the light to illuminate the photo-sensitive layer is distorted, thereby the circuit pattern is not formed clearly.
For that purpose, in order to form the surface smooth of the insulation resin layer laminated on the circuit pattern formed on the circuit substrate, the heating plate 30 of the vacuum hot press to laminate-mold the circuit substrate has to be also formed with a rigidity member and its opposing surface 35 is made flat.
In the case of forming the above IC card, after molding a vinyl chloride resin is easy to form in working of a pear skin on the surface, engraving and adhering of magnetic tape. However, since the vinyl chloride resin is molten at the time of forming an IC card, necessary information and design are not in advance printed, which has to be carried out by a separated process after molding. Further, it is required to have finished flat in a high level on the surface of the IC card to print any necessary information and any design after molding the IC card. On the other hand, although PET comparing to the vinyl chloride resin is high in its melting point, any necessary information and any design can be printed in advance, it is difficult to work the IC card for such as the pear skin after molding. Therefore, it is a problem to employ PET, accordingly recently, in order to avoid both inconveniences, it has been tried to make use of vinyl chloride resin as the basic material and laminate the IC chip and the coil in the embedding layer of the adhesive.
Further, when pressurizing the material to laminate molding for embedding in the resin layer the lamination member such as IC chip between the heating plates using the above hot press, although it can be molded in its surface smooth, since the heating plate forming a pressure surface has to consist of a highly rigid body not deformable and weighed to some extent, there has been a problem of occurrence of brittle fracture because it is difficult to carry out a fine regulation of the pressurizing force of the cylinder mechanism. In the case where the IC chip as a lamination member is broken, the molded product can not function as IC card at all, so that it has been deteriorated and becomes bad in its yield.
Further, when the heating plate pressurizes the material, the molten resin of the resin layer may be leaked out from the edge of the material, which causes the width and length of the products become large, in addition, the thickness thereof to become thinner than the one set in advance, thereby there can be a problem that the set shape and dimension can not be kept, and there may be a problem to need a post-treatment in taking away such leakage.
Furthermore, due to the shrinkage of the molten resin layer and the flowing of the molten resin around the IC chip or the coil, the sink of the surface of the products is generated and the surface can not keep the flatness. Such products which are deteriorated in flatness have the problem that after molding in IC card the necessary information and design can not be printed. And, since any IC card of vinyl chloride resin can not be printed in advance before molding with the necessary information or the design, it has been a problem where the printing processes of the necessary information and the design are increased.
On the other hand, in the case where, using above hot press, a circuit substrate is laminate-molded, as shown in FIG. 19, on the surface of the circuit substrate ha to be laminated with an insulation resin layer hb, a concavo-convex circuit pattern ha 2 is formed. Therefore, in the case where on one surface of the circuit substrate an insulation resin layer hb is laminate-molded, when the circuit substrate ha and the fluidized insulation resin layer hb are pressurized between the opposing surfaces 35 formed flat of the heating plates 30 having rigidity, as shown in FIG. 20, since the circuit pattern ha 2 of the circuit substrate is adapted to be pressed partially by the surface 35 of the heating plate 30, the circuit substrate ha is deformed and the thickness of the insulation resin layer hb does not become uniform. And, the laminated products taken out from between the heating plates 30 (the circuit substrate laminated with the insulation resin layer), as shown in FIG. 21, while keeping the thickness of the insulation resin layer hb not uniform, the distorted circuit substrate ha returns resiliently to the original shape. When this circuit substrate ha returns approximately to the original shape, the surface of the laminated insulation resin layer hb is distorted as waving and does not become smooth, thereby at the later exposing process of the photo-resist forming layer the light to be illuminated is generated with a distortion and accordingly the light to be illuminated appropriately is adapted to be distorted in its illumination, thereby a problem which causes the circuit pattern ha 2 to be formed not precisely has occurred.
Further, as shown in FIGS. 20 and 21, at the time when the fluidized insulation resin layer hb is pressurized, it is leaked out of the edge of the circuit substrate (sign S in FIG. 20) to cause the thickness of the insulation resin layer ha1 to be thinner, and there has been a problem that the insulation property of the insulation resin layer ha 1 is not ensured, which is caused by a incidental contact of the circuit pattern ha 2 embedded in the thickness direction to generate the deterioration of insulation. In addition, due to the solidifying of the insulation resin layer while being leaked out of the edge of the insulating resin layer hb (sign E of FIG. 21), thereby, there is a problem in which the laminated material can not be formed in a desired dimension and shape.